comm(1)

NAME

comm- select or reject lines common to two files

SYNOPSIS

comm [-123] file1file2

DESCRIPTION

The comm utility will read file1 and file2, which should
be ordered in the current collating sequence, and produce three text columns as output: lines only in file1; lines only in file2; and lines in both files.

If the input files were ordered according to the collating sequence of the current locale, the lines written will be in the collating sequence of the original lines. If not, the results are unspecified.

OPTIONS

The following options are supported:

-1

Suppress the output column of lines unique to file1.

-2

Suppress the output column of lines unique to file2.

-3

Suppress the output column of lines duplicated in file1 and file2.

OPERANDS

The following operands are supported:

file1

A path name of the first file to be compared. If file1 is -, the standard input is used.

file2

A path name of the second file to be compared. If file2 is -, the standard input is used.

USAGE

See largefile(5) for the description of the behavior of comm when encountering files greater than or equal to 2 Gbyte ( 231 bytes).

EXAMPLES

Example 1 Printing a list of utilities specified by files

If file1, file2, and file3 each contained a sorted list of utilities:

example% comm -23 file1 file2 | comm -23 - file3

would print a list of utilities in file1 not specified by either of the other files. The entry:

example% comm -12 file1 file2 | comm -12 - file3

would print a list of utilities specified by all three files. And the entry:

example% comm -12 file2 file3 | comm -23 -file1

would print a list of utilities specified by both file2 and file3, but not specified in file1.

ENVIRONMENT VARIABLES

See environ(5) for descriptions of the following environment variables that affect the execution of comm: LANG, LC_ALL, LC_COLLATE, LC_CTYPE, LC_MESSAGES, and NLSPATH.